Investigation of single and multiple effects of lactic acid, cetylpyridinium chloride and trisodium phosphate on the chicken carcasses contaminated with E. coli O157:H7 and Listeria monocytogenes

The study was conducted to investigate the effects of cetylpyridinium chloride (CPC), trisodium phosphate (TSP), lactic acid (LA) and their combinations on survival of E. coli O157:H7 and L. monocytogenes on broiler carcasses. Broiler carcasses were contaminated with 5-strains of E. coli O157:H7 (E. coli O157:H7 ATCC E0139, E. coli O157:H7 ATCC 43895, E. coli O157:H7 ATCC 43895 Rif (+), E. coli O157:H7 ATCC 51657 Rif (+), E. coli O157:H7 ATCC 43894) and 10-strains of L. monocytogenes (L. monocytogenes RSKK 472, L. monocytogenes N-7155, L. monocytogenes RSKK 475, L. monocytogenes RSKK 476, L. monocytogenes N-7144, L. monocytogenes N-7144 Rif (+), L. monocytogenes RSKK 474, L. monocytogenes NCTC 2167, L. monocytogenes RSKK 02028, L. monocytogenes N-7143). Then, the carcasses were subjected to decontamination treatments with 0.2 % or 0.4 CPC, 8 % or 12 % TSP, 2 % or 4 LA, % 2 LA + % 8 TSP, 0.2 % CPC + 2 % LA or 0.2 % CPC + 8 % TSP at 20 oC for 15 min. Effects of treatments on survival of the pathogens were determined. The differences in levels of both pathogens between before and after were significant. The most effective decontaminant on E. coli O157:H7 was 0.4 % CPC with 3.36 log10 cfu/ml reduction followed by 0.2 % CPC+% 2 LA with 2.97 log10 cfu/ml reduction, 0.2 % CPC+ 8 % TSP with 2.69 log10 cfu/ml reduction, 12 % TSP with 2.65 log10 cfu/ml reduction, 0.2 % CPC with 2.64 log10 cfu/ml reduction, 2 % LA+ 8 % TSP with 2.50 log10 cfu/ml reduction, 8 % TSP with 2.46 log10 cfu/ml reduction, 4 % LA with 2.44 log10 cfu/ml and 2 % LA with reduction 1.91 log10 cfu/ml. The most effective decontaminant on L. monocytogenes was 0.4 % CPC with 5.04 log10 cfu/ml reduction followed by, 0.2 % CPC+ 2 % LA with 4.06 log10 cfu/ml reduction, 0.2 % CPC with 3.89 log10 cfu/ml reduction, 0.2 % CPC+ 8 % TSP with 3.42 log10 cfu/ml reduction, % 2 LA+% 8 TSP with 2.60 log10 cfu/ml reduction, % 12 TSP with 2.38 log10 cfu/ml reduction, 4 % LA with 2.15 log10 cfu/ml reduction, 8 % TSP with 2.09 log10 cfu/ml and 2 % LA with 1.84 log10 cfu/ml reduction. As a result, the most effective decontaminant against E. coli O157:H7 and L. monocytogenes on chicken carcasses was found to be CPC followed by TSP and LA. Key Words: Broiler carcass, Cetylpyridinium Chloride (CPC), Trisodium Phosphate (TSP), Lactic acid, E. coli O157:H7, L. monocytogenes.